CN110732188A - In-pipe phase-separated split-flow high-flow gas-liquid separation device and method - Google Patents

Abstract

An in-pipe phase-separated split-flow high-flow gas-liquid separation device and method, the device is mainly composed of a main pipeline, a swirl device, an annular window, a liquid collection pipe and an inclined drainage pipe; The liquid two-phase fluid is separated into a uniform swirl liquid film and a gas core. When the swirl liquid film and the gas core flow through the annular window, the fluid flows in two ways: one is most of the gas core and still flows in the main pipe. And directly bypass to the gas outlet; the other is the swirl liquid film and a small part of the gas, which enters the liquid collection tube through the upper half of the annular window, and this small part of the gas relies on centrifugal force and gravity in the liquid collection tube. After the liquid film is separated, it returns to the main pipeline through the lower half of the annular window and flows out from the gas phase outlet of the separator; since the separation device bypasses most of the gas, only a part of the two-phase flow needs to be separated. It is more compact, the volume is greatly reduced, the cost is reduced, and the resistance is smaller than the traditional separator.

Description

In-pipe phase-separated split-flow high-flow gas-liquid separation device and method

technical field

The invention relates to the technical field of gas-liquid two-phase fluid separation, in particular to an in-pipe phase-separated split-flow high-flow gas-liquid separation device and method.

Background technique

Gas-liquid two-phase fluid separation technology is widely used in petrochemical, energy power and natural gas fields. The traditional gas-liquid separator mainly uses gravity and centrifugal force to separate the liquid phase, such as the most widely used cyclone separator. However, in order to prevent the tearing of the liquid film and the liquid phase entrainment at the gas phase outlet caused by the high upward airflow velocity in the separator, there are clear restrictions on the upward airflow velocity in the separation cylinder. According to the design experience, the range of the rising gas velocity is generally 0.1 m/s～4.0m/s, so the diameter of the separator cylinder is several times the diameter of the inlet, resulting in most of the traditional separators belonging to the pressure vessel type, which is bulky, heavy, expensive, and inconvenient to maintain. In order to reduce costs, many compact gas-liquid separators have appeared in recent years.

Compact Separators for Wet Gas Applications[J].Journal of Energy Resources Technology,2003,125(1).)提出了一种改进型的GLCC，通过在GLCC上部加装AFE，利用旋流作用来分离气路出口中的液相夹带，入口气相折算流速提高到18m/s。Column Cyclone Separator (GLCC) is a compact separator proposed by the University of Tulsa. It is a vertical tube with inclined tangential inlet and gas and liquid outlet. It relies on cyclone centrifugal force to achieve gas flow. , liquid separation. If the rising gas velocity is too high, it will cause serious droplet entrainment at the gas outlet. Therefore, in conventional GCLL, the converted gas velocity at the inlet is usually less than 9.2 m/s. Wang et al. (2003) (Wang S., Gomez LE, Mohan RS, et al. Gas-LiquidCylindrical Cyclone

Compact Separators for Wet Gas Applications[J].Journal of Energy Resources Technology,2003,125(1). An improved GLCC is proposed. By adding AFE to the upper part of GLCC, the gas outlet is separated by cyclone. The liquid phase entrainment in the inlet gas phase is increased to 18m/s.

Rotary vane gas-liquid separators are widely used in nuclear power plants to improve the dryness of steam at the outlet of steam generators. Axial flow vanes are used to make the fluid rotate in the separator. Under the action of centrifugal force, the gas-liquid two-phase fluid flows to form the liquid film and the gas core flow. When flowing through the orifice plate installed downstream of the blade, the liquid film is discharged through the down pipe, and the gas core flows out through the orifice plate. However, in the process of separating the gas core and the liquid film, the gas core will undergo a sudden contraction and acceleration at the orifice plate, and it is easy to entrain the liquid phase into the gas outlet, so the inlet flow rate is also limited. The converted speed is generally less than 24m/s. Similar to this includes the Russian MOЦKTИ type separator used in the once-through boiler. Unlike the rotary vane gas-water separator, the steam and water flow in the same direction and flow downward together, but they also rely on centrifugal force to generate a liquid film. By coaxially installing an inner cylinder with a slightly smaller inner diameter in the separation cylinder, the liquid film is discharged from the annular space between the outer wall of the inner cylinder and the inner wall of the outer cylinder, and the gas core enters the inner cylinder and flows to the downstream outlet. In the process of separating the liquid film and the gas core, there is still a phenomenon that the gas core flows into the inner cylinder and shrinks and flows, and the flow rate is too high to easily entrain droplets. In addition, the gas-liquid two-phase fluid is still separated in the separation cylinder. The diameter of the separation cylinder is several times the diameter of the inlet pipe, and the separator is very large and belongs to a conventional separator.

US patents US3884660 and US4180391 propose a tubular gas-liquid separator. A settling chamber contains a main pipeline, in which a swirling device is installed, and the main pipeline is provided with one or two annular injection ports downstream of the swirling device. After the gas-liquid two-phase fluid flows through the swirl device, since part of the liquid phase does not have enough kinetic energy to overcome the resistance of the annular nozzle, in order to allow the entire liquid film to be discharged through the annular nozzle, a part of the gas must not be ejected through the annular nozzle together with the liquid film. into the settling chamber and finally separated by gravity in the settling chamber. However, this makes it still a vessel-type separator, which is bulky.

Another method for separating gas-liquid two-phase fluids is to make holes or grooves in the pipe wall. US patents US4856461, US4909067 and US7381235 all utilize this method. US patents US4856461 and US4909067 propose a gas-liquid two-phase fluid separation device. The gas-liquid two-phase fluid flows through the coaxial helical ties installed in the tube to generate swirling motion. Under the action of centrifugal force, the droplets are separated from the pipe through the holes in the pipe wall and fall into the liquid collector. However, when the airflow velocity exceeds 4.9 m/s, the droplets cannot be completely removed. Wen Yiqian (2009) (Literature: Wen Yiqian. Experimental Research on Gas-liquid Separator with Porous Tubes [D]. Xi'an: Xi'an Jiaotong University, 2009) Based on this, an improved gas-liquid separator was proposed. A conical tube with holes in the tube wall was replaced, and a swirling device was installed in the center of the inlet of the conical tube. The experimental results show that the converted flow velocity of the gas phase can reach 30m/s. US patent US7381235 is similar to this, in which grooves are made on the wall of the tube, and the liquid phase is separated by combining centrifugal force. These methods all try to separate the liquid phase in the radial direction (that is, the direction of centrifugal force), but the liquid phase will continue to move along the tangential direction when it leaves the wall due to inertia after leaving the tube wall. Therefore, this method The resistance of the liquid phase passing through the radial holes or grooves of the pipe wall is greatly increased, which is not conducive to the separation of the liquid phase.

To sum up, it is not difficult to make the gas-liquid two-phase flow form the liquid film and the gas core by the centrifugal method, but there is still a strong coupling between the liquid film and the gas core flowing together, so the last step to separate the gas core and the liquid film is not difficult. It is carried out under the condition of low flow rate, so the volume of the separator is large and the cost is expensive.

SUMMARY OF THE INVENTION

In view of the above-mentioned deficiencies in the prior art, the present invention proposes an in-pipe phase-separated split-flow high-flow gas-liquid separation device and method.

The "phase" in the present invention refers to each part of the multiphase fluid with the same physical properties, such as gas phase, liquid phase, oil phase, and water phase. The gas phase and liquid phase can be either single-component substances or a homogeneous mixture of multi-component substances, such as air, crude oil, etc. In-pipe phase separation refers to converging and isolating each phase into a specific area in the pipe to flow, and there is a clear and clear phase interface between each phase. The method of the invention first converts the gas-liquid two-phase fluid into a special annular flow pattern through the phase separation technology in the pipe, that is, a liquid film of uniform thickness is formed near the pipe wall, the gas core flows in the center of the pipe, and there is almost no small liquid in the middle of the gas core. drop. When the liquid film and gas core flow through the annular window, it is divided into two flows: one is for most of the gas core, which still flows in the pipeline and bypasses directly to the outlet; the other is for the swirling liquid film and a small part of the gas, passing through the annular window The upper part of the gas enters the liquid collection pipe, and this small part of the gas is separated from the liquid phase by centrifugal force and gravity in the liquid collection pipe, and then returns to the main pipeline through the lower part of the annular window and flows out from the outlet of the separator, and the liquid phase passes through the liquid collection pipe. Bottom drain. Since most of the gas cores are directly bypassed, the liquid collection pipe only needs to separate a small part of the fluid in the flow, which greatly reduces the volume of the separator and reduces the cost. Compared with the traditional separator, the resistance is smaller, and it can It is widely used in petrochemical, offshore platforms, natural gas pipelines to remove liquid accumulation, gas-liquid two-phase fluid online measurement and other fields.

In order to achieve the above object, the technical scheme adopted in the present invention is:

An in-pipe phase-separated split-flow high-velocity gas-liquid separation device, comprising a phase-separated upstream main pipeline 1 and a downstream main pipeline 8, and the upstream main pipeline 1 and the downstream main pipeline 8 pass through an externally wrapped liquid collection pipe 4. Consolidated and communicated, a swirl device 2 is installed above the liquid collection pipe 4 in the upstream main pipeline 1, and the separation section of the upstream main pipeline 1 and the downstream main pipeline 8 forms an annular window 3 in the liquid collection pipe 4 ; Between the upstream main road pipeline 1 and the liquid phase collection pipe 4, the vertebral canal 7 is guided by the liquid film; Outside the annular window 3 connected with the upstream main pipeline 1 and the outlet of the downwardly inclined drain pipe 5, the liquid collection pipe 4 forms a closed space;

The length of the annular window 3 formed in the liquid phase collecting pipe 4 by the upstream main pipeline 1 and the downstream main pipeline 8 is adjusted by mechanical structure, and the length of the annular window 3 is 0.1 to 4 times the diameter of the upstream main pipeline 1 .

The liquid film guiding vertebral canal 7 at the junction of the upstream main road pipeline 1 and the liquid phase collecting pipe 4 is a conical pipe, the inlet diameter of which is equal to the upstream main road pipeline 1, the outlet diameter is larger than the inlet diameter, and the inner wall is connected to the upstream main road pipeline 1. The included angle of the axes is 0° to 60°.

The inlet of the downstream main road pipeline 8 has no outer chamfer or has an outer chamfer.

The part of the downstream main pipeline 8 located in the liquid phase collecting pipe 4 is provided with a tightly connected outer sleeve 9 or an inner sleeve 10, and the outer sleeve 9 or the inner sleeve 10 can be freely adjusted beyond the height of the lower main pipeline 8 ; or the part of the downstream main pipeline 8 in the liquid phase collecting pipe 4 does not have any casing.

The liquid phase collection pipe 4 is constituted by a single whole; or the liquid phase collection pipe is composed of the liquid phase collection upper pipe 12 and the liquid phase collection lower pipe 11 by being sleeved on the liquid phase collection upper pipe 12 and the liquid phase collection lower pipe 11. The external connection sleeves 13 are connected to form, the installation position of the connection sleeve 13 completely covers the annular window 3 or partially covers the annular window 3 , and the length of the annular window 3 is adjusted through the connection sleeve 13 .

The upstream main pipeline 1, the downstream main pipeline 8, the liquid collection pipe 4, the swirl device 2, the liquid film guide vertebral canal 7, the liquid phase collection upper pipe 12, the liquid phase collection lower pipe 11, and the large casing 13 are all arranged coaxially.

The included angle between the axis of the downwardly inclined liquid discharge pipe 5 and the axis of the liquid phase collecting pipe 4 is less than 50°.

The described two-phase fluid separation method of a split-flow high-velocity gas-liquid separation device in a pipe: when the high-speed gas-liquid two-phase fluid flows through the cyclone device 2 in the upstream main pipeline 1, under the action of centrifugal force , the gas-liquid two-phase fluid is divided into a uniform swirl liquid film close to the pipe wall and a gas core flowing in the center of the pipeline in the upstream main pipeline 1; when the swirl liquid film and gas core are in the upstream main pipeline 1 When it flows through the downstream annular window 3, it is divided into two flows: one is most of the gas core, which still flows in the upstream main pipeline 1 and is directly bypassed to the gas outlet, that is, the downstream main pipeline 8 outlet; All the way is the swirl liquid film and a small part of the gas, which enters the liquid collection pipe 4 through the upper part of the annular window 3. This small part of the gas is separated in the liquid collection pipe 4 under the action of gravity and centrifugal force, and then passes through the lower part of the annular window 3. Return to the downstream main pipeline 8 and discharge from the gas phase outlet, and the liquid phase is discharged through the downward inclined liquid discharge pipe 5 at the bottom or bottom of the liquid collecting pipe 4 .

Compared with the prior art, the present invention has the following characteristics:

(1) Most of the incoming gas is directly bypassed to the gas outlet, and the separator only needs to separate a part of the incoming flow, which greatly reduces the volume of the separator, makes the structure more compact and lowers the cost.

(2) The separator is small in size, and the separation efficiency can be adjusted by adjusting the length of the annular window according to the incoming flow rate and separation needs. The maintenance is simple and convenient, and the phase separation technology can be widely used in a variety of flow patterns.

(3) The separator only needs to separate a part of the incoming flow, and the resistance of the separator is correspondingly reduced, which improves the economy.

Description of drawings

FIG. 1 is a schematic structural diagram of the in-pipe phase-separated split-flow high-flow gas-liquid two-phase fluid separation device of the present invention.

Figure 2 is another structural schematic diagram of the downstream main pipeline of the present invention; wherein Figure 2(a) is a schematic diagram of the downstream main pipeline connected to the outer casing, and Figure 2(b) is a schematic diagram of the downstream main pipeline connected to the inner casing.

Figure 3 is a schematic diagram of another structure of the liquid collecting pipe.

Detailed ways

The present invention will be described in more detail below with reference to the accompanying drawings.

Example 1

As shown in FIG. 1 , an in-pipe phase-separated split-flow high-flow gas-liquid separation device is mainly composed of an upstream main pipeline 1 , a downstream main pipeline 8 , a liquid phase collection pipe 4 , a cyclone device 2 , and an annular window 3 . The specific connection method is as follows: the upstream main pipeline 1 and the downstream main pipeline 8 are consolidated and communicated through the liquid collection pipe 4 wrapped on the outside. The main pipeline 1 and the downstream main pipeline 8 form an annular window 3 in the liquid collection pipe 4; the upstream main pipeline 1 and the liquid phase collection pipe 4 are connected by a liquid film guiding vertebral canal 7; the liquid collection pipe The lower part or bottom of 4 is communicated with the downwardly inclined discharge pipe 5, and the liquid collection pipe 4 is formed in addition to the annular window 3 connected with the upstream main pipe 1 and the outlet of the downwardly inclined discharge pipe 5. A closed space; a regulating valve 6 is installed downstream of the downwardly inclined discharge pipe 5.

The length of the annular window 3 formed in the liquid phase collecting pipe 4 by the upstream main pipeline 1 and the downstream main pipeline 8 can be adjusted by mechanical structure.

The liquid film guiding vertebral canal 7 at the connection of the upstream main pipeline 1 and the liquid phase collecting pipe 4 is a conical tube, its inlet diameter is equal to the upstream main pipeline 1, the outlet diameter is larger than the inlet diameter, and the angle between the inner wall and the axis is 0° ~60°.

The inlet of the downstream main pipeline 8 may not have an external chamfer, or may have an external chamfer.

As shown in FIG. 2 , it is another structural diagram of a part of the downstream main pipeline 8 in the liquid phase collecting pipe 4 . A section of tightly connected outer sleeve 9 is arranged outside the downstream main pipeline 8, as shown in Figure 2(a), or in the downstream main pipeline 8, there is a tightly connected inner sleeve 10, as shown in Figure 2(b) ), the outer casing 9 or the inner casing 10 can freely adjust the height beyond the inlet of the downstream main pipeline 8 to adjust the length of the annular window 3 .

The angle between the axis of the downwardly inclined discharge pipe 5 and the axis of the liquid phase collecting pipe 4 is less than 50°. The downward slope of the drain pipe 5 can better prevent the gas from entering the liquid outlet.

Example 2

As shown in FIG. 3 , the downstream main pipeline 8 is not provided with a casing. The liquid phase collection pipe is composed of the liquid phase collection upper pipe 12, the liquid phase collection lower pipe 11 and the connecting sleeve 13. The liquid phase collection upper pipe 12 and the lower pipe 11 are sleeved on the liquid phase collection upper pipe 12 and the liquid phase collection lower pipe. The connecting sleeve 13 outside the pipe 11 is connected, and the connecting sleeve 13 can adjust the length of the liquid phase collecting pipe through a mechanical device structure (such as gear drive or screw connection), so as to achieve the purpose of adjusting the length of the annular window 3 . In Example 2, the other structures of the phase-separated split-flow high-speed gas-liquid separation device in the tube are exactly the same as those in Example 1.

The main pipelines 1 and 8, the liquid collection pipe 4, the swirl device 2, the liquid film guide vertebral canal 7, the liquid phase collection upper pipe 12, the liquid phase collection lower pipe 11, and the large casing 13 are all coaxially arranged.

The method for separating high-speed gas-liquid two-phase fluid with phase separation in the pipe of the present invention: when the high-speed gas-liquid two-phase fluid flows through the cyclone device 2 in the upstream main pipeline 1, under the action of centrifugal force, the gas-liquid two-phase fluid The upstream main pipeline 1 is divided into a uniform swirling liquid film close to the pipe wall and a gas core flowing in the center of the pipe. When the swirl liquid film and the gas core flow through the annular window 3 downstream of the upstream main pipeline 1, the fluid is divided into two flows: one is most of the gas core, which still flows in the upstream main pipeline 1 and is directly bypassed to the outlet of the gas path; the other path is the swirl liquid film and a small part of the gas, which enters the liquid collection pipe through the upper part of the annular window 3, and this small part of the gas is separated in the liquid collection pipe 4 under the action of gravity and centrifugal force. It returns to the downstream main pipeline 8 through the lower part of the annular window 3 and is discharged from the gas outlet, and the liquid phase is discharged through the downward inclined discharge pipe 5 at the lower part of the liquid collecting pipe 4 or the bottom. Wherein, the length of the annular window 3 can be adjusted. When flowing through the annular window 3 , the second branch, that is, the flow rates of the gas and the liquid phase entering the liquid collecting pipe 4 increases as the length of the annular window 3 increases. However, if the length of the annular window 3 is too small, the gas entering the liquid collecting pipe 4 will return to the upstream main pipeline 1 prematurely, which is very likely to cause secondary entrainment of the unseparated liquid in the liquid collecting pipe 4; when the length of the annular window 3 is too large , will cause the flow resistance to increase. According to different inlet flow rates and actual required separation efficiency, the appropriate length of the annular window 3 can be adjusted and selected.

Claims (9)

1. A high-flow-rate gas-liquid separator with separated internal phase and divided flow is characterized by comprising an upstream main pipeline (1) and a downstream main pipeline (8) which are separated from each other, wherein the upstream main pipeline (1) and the downstream main pipeline (8) are fixedly connected and communicated through a liquid collecting pipe (4) wrapped outside, a cyclone device (2) is arranged above the liquid collecting pipe (4) in the upstream main pipeline (1), the separation sections of the upstream main pipeline (1) and the downstream main pipeline (8) form annular windows (3) in the liquid collecting pipe (4), the upstream main pipeline (1) and the liquid collecting pipe (4) are connected through a liquid film guiding conical pipe (7), the lower part or the bottom of the liquid collecting pipe (4) is communicated with the main pipeline (5), the liquid collecting pipe (4) except for the annular window (3) connected with the upstream main pipeline (1) and the outlet of a downward-inclined liquid discharging pipe (5), the liquid collecting pipe (4) forms closed spaces, and a downstream liquid discharging pipe (5) is provided with a downward-inclined adjusting valve ().
2. 2. The in-tube phase-separated flow-splitting high-flow-rate gas-liquid separation device according to claim 1, wherein the length of an annular window (3) formed by the upstream main path pipeline (1) and the downstream main path pipeline (8) in the liquid phase collecting pipe (4) is adjusted by a mechanical structure, and the length of the annular window (3) is 0.1-4 times of the diameter of the upstream main path pipeline (1).
3. 3. The device for separating high-flow-rate gas and liquid in-tube and dividing flow according to claim 1, wherein the liquid film guiding conical tube (7) at the junction of the upstream main conduit (1) and the liquid phase collecting tube (4) is conical tube, the diameter of the inlet is equal to that of the upstream main conduit (1), the diameter of the outlet is greater than that of the inlet, and the included angle between the inner wall and the axis of the upstream main conduit (1) is 0-60 °.
4. 4. the in-tube split-flow high-flow-rate gas-liquid separator according to claim 1, wherein the inlet of the downstream main conduit (8) has no or no external chamfer.
5. 5. The in-tube separated-flow-dividing high-flow-rate gas-liquid separation device according to claim 1, wherein the part of the downstream main conduit (8) inside the liquid-phase collection pipe (4) is provided with sections of tightly connected outer sleeves (9) or inner sleeves (10), the height of the outer sleeves (9) or inner sleeves (10) exceeding the height of the downstream main conduit (8) can be freely adjusted, or the part of the downstream main conduit (8) inside the liquid-phase collection pipe (4) is free from any sleeves.
6. 6. The in-tube separated-flow-dividing high-flow-rate gas-liquid separation device according to claim 1, wherein the liquid phase collection tube (4) is composed of single bodies, or the liquid phase collection tube is composed of a liquid phase collection upper tube (12) and a liquid phase collection lower tube (11) which are connected through a connecting sleeve (13) sleeved outside the liquid phase collection upper tube (12) and the liquid phase collection lower tube (11), the installation position of the connecting sleeve (13) completely covers the annular window (3) or covers part of the annular window (3), and the length of the annular window (3) is adjusted through the connecting sleeve (13).
7. 7. The in-tube phase-separated and split-flow high-flow-rate gas-liquid separation device according to claim 1, wherein the upstream main pipeline (1), the downstream main pipeline (8), the liquid collection pipe (4), the cyclone device (2), the liquid film guiding conical pipe (7), the liquid phase collection upper pipe (12), the liquid phase collection lower pipe (11), and the large casing pipe (13) are all coaxially arranged.
8. 8. The in-tube split-flow high-flow-rate gas-liquid separation device according to claim 1, wherein the angle between the axis of the downward-inclined liquid discharge tube (5) and the axis of the liquid phase collection tube (4) is less than 50 °.
9. 9. A method for separating two-phase fluid in type of in-tube separated split-flow high flow rate gas-liquid separation apparatus as claimed in any claims 1 to 8, wherein the high speed gas-liquid two-phase fluid is separated into a uniform swirling liquid film closely attached to the tube wall and a gas core flowing in the center of the tube in the upstream main flow pipe (1) by the centrifugal force after passing through the swirling device (2) in the upstream main flow pipe (1), when the swirling liquid film and the gas core flow through the downstream annular window (3) in the upstream main flow pipe (1), the swirling liquid film and the gas core flow in two ways, wherein is the majority of gas core, which still flows in the upstream main flow pipe (1) and is bypassed directly to the outlet of the gas path, i.e. the outlet of the downstream main flow pipe (8), and is the swirling flow and minority of gas, which enters the liquid collection pipe (4) through the upper part of the annular window (3), and a small portion of the gas which is separated by the gravity and centrifugal force in the liquid collection pipe (4) returns to the lower part of the downstream main flow pipe (8) and is discharged from the liquid discharge pipe (5) through the lower part of the liquid collection pipe (4).

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